10 September 2019:
The detection of Cryptosporidium in public drinking water supplies has increased over the past three years, a new Environmental Protection Agency report has found.
An analysis of the quality of public drinking water supplies in 2018 shows that while overall quality remains high, the incidence of Cryptosporidium detections has increased in the past three years. This, the environment watchdog says, poses a serious risk to human health.
Cryptosporidium is a parasite that is found in human or animal waste. If present in drinking water, it can cause gastrointestinal illness, such as persistent diarrhea, particularly in young children and the elderly.
The EPA detected the parasite in 25 public water supplies in 2018, up from 17 in 2017 and 12 in 2016, with inadequate processes in place to treat or remove it in several locations.
Dr Tom Ryan, Director of the EPA’s Office of Environmental Enforcement said that the Agency has ensured that Irish Water has investigated each of these detections, especially in light of the “upward trend” in contamination.
The EPA also laid out several priorities that it wants to see Irish Water address on a national level, including preventing long-term boil water notices by providing robust disinfection systems.
“Irish Water must make certain that water treatment plants are properly and effectively operated to protect public health. Those plants without appropriate treatment for Cryptosporidium need to be prioritised for investment by Irish Water,” he added.
The EPA has added several supplies to its Remedial Action List (RAL) following its audits of drinking water plants. Irish Water has to prioritise sites on the list and develop action plans for improvements to be completed, by set dates. The list includes 15 supplies with inadequate treatment for Cryptosporidium.
Forty-four boil water notices and a further 15 water restrictions were in place in 2018, affecting more than 100,000 people across 16 counties.
The largest supply affected by a boil notice or water restriction in 2018 was the Lough Talk supply in Co. Sligo, which serves 12,576 people. This boil notice was issued following the detection of Cryptosporidium. It is proposed that a new water treatment plant is constructed to remedy the issue, although this will not be completed until December 2020.
The EPA is also pushing for Irish Water to ensure that organic matter in water is removed prior to disinfection in order to minimise harmful disinfection by-products such as Trihalomethanes (THM). Limits were exceeded in 54 supplies last year, according to the EPA.
The chemical is a by-product formed when chlorine used to disinfect drinking water reacts with organic matter such as runoff from drainage at peat extraction sites. Prolonged consumption of drinking water with high THM levels is linked to liver, kidneys, and bladder diseases, as well as cancer and issues with the central nervous and reproduction systems.
THMs can be absorbed when water comes in contact with skin, through drinking contaminated water or consuming food prepared in this water. Last summer, the European Commission opened an infringement case against Ireland for failing to ensure drinking water for over 500,000 consumers is safe from excessive levels of THMs.
E. coli was also detected at least once in 12 supplies in 2018. Another EPA report released last November on private water supply found that 51 supplies serving the likes of nursing homes, crèches and hotels tested positive for the bacteria.
Consuming water contaminated with E. Coli may lead to gastrointestinal illnesses and in more severe cases may result in kidney failure.
Pesticides limits were also exceeded in 34 supplies last year, compared to 48 in 2017. ‘Pesticides’ includes a wide range of products, but in Ireland, herbicides pose the greatest threat to drinking water.
At the end of 2018, the EPA was investigating 42 supplies serving almost 283,500 people, due to failures to meet the pesticide standard. Three-quarters of all failures were linked to the herbicide MCPA, a widely used herbicide applied to grassland for ragwort, rush, and thistle control.